Synthesis and Characterization of Hydroxyethylstarch Hydrogels as Drug Delivery Systems

A successful application of proteins as active ingredients depends on the availability of an efficient delivery and release system, which allows a controlled release of physiological amounts of proteins next to the target tissue over a certain period of time. The approach to such a drug delivery system is the entrapment of proteins in a hydrogel matrix. With the ability of hydrogels to incorporate a huge amount of water or buffer, they offer optimal conditions for long in vivo-lifetimes of proteins. Our hydrogel delivery system bases on photocrosslinking of hydroxyethylmethacrylate-hydroxy-ethylstarch (HESHEMA, Fig. 1) in the presence of proteins (Fig. 2).

Fig. 1 HESHEMA

Fig. 2 Photocrosslinking

HES has been used in medicine for a long time, so that the physiological compatibility of the hydrogels can be assumed. Modifications in the Degree of substitution of the crosslinkable HEMA-group afford hydrogels with different mesh sizes. Furthermore this hydrogelmatrix is biodegradable, so that a continuous release of active ingredients in the course of the erosion of the hydrogel and diffusion is possible.